I would email the "Mr. Zero" teacher with your understanding of the situation and ask him his take on the situation and ask what makes him think that's an acceptable way to interact with students. I would also cc the principal. That behavior is way out of line.

But I think you should also consider that your son might be having trouble with social cues and behaviors. It sounds like there have been plenty of instances you're aware of where you think he's rubbing people the wrong way, talking too much, and leaving people with the impression he's a know-it-all. Even if that's not his intent, it seems like he needs help with his behavior so people don't get that impression (assuming you don't want that).